20190118 Ver 1_SWMP 17BP.5.R.66_20190125

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Highway North Carolina Department of Transportation <>'` �
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STORMWATER MANAGEMENT PLAN �='"%
(Version 2.07; Released October 2016) FOR NCDOT PROJECTS
WBS Element: 17BP.5.R.66 TIP No.: County(ies): Franklin Page 1 of 1
General Project Information
WBS Element: 17BP.5.R.66 TIP Number: Project Type: Bridge Replacement Date: 1/8/2019
NCDOT Contact: Matthew Lauffer, PE Contractor / Desi ner: K le Stoffer, EI
Address: NCDOT Hydraulics Unit Address: HDR Engineering, Inc.
1590 Mail Services Unit 555 Fayetteville Street, Suite 900
Ralei h, NC 27560 Ralei h, NC 27601
Phone: [phone] Phone: [phone]
Email: mslauffer ncdot. ov Email: k le.stoffer hdrinc.com
City/Town: Louisbur Count ies : Franklin
River Basin s: Tar-Pamlico CAMA County? No
Wetlands within Project Limits? Yes
Pro'ect Description
Project Length (lin. miles or feet): 0.114 miles Surrounding Land Use: Low Residential, Wooded
Proposed Pro'ect Existin Site
Pro'ect Built-Upon Area ac. 0.28 ac. 0.25 ac.
Typical Cross Section Description: Pete Smith Road (SR 1412): 2 paved lanes (total 20' wide), 4' shoulder on each side (7' Pete Smith Road (SR 1412): 2 paved lanes (total 18' wide), 5' shoulder on each side
with guardrail).
Annual Avg Daily Traffic (veh/hr/day): Desi n/Future: 920 Year: 2025 Existin : 460 Year: 2013
General Project Narrative: The North Carolina Department of Transportation (NCDOT) has proposed to replace Franklin County Bridge #50 on Pete Smith Road (SR 1412) over Devils Cradle Creek. The
(Description of Minimization of Water existing structure is a six span bridge (1@10'2"; 1@10'3"; 1@9'6"; 1@10'6"; 1@14'9"; 1@15'5") and is a timber deck on I-Beams supported by timber caps on timber piles for
Quality Impacts) the interior and end bents. The proposed structure is a single span (1 @90'), 33" box beam with 4' deep caps. This structure has been designed to have as little environmental,
wetland, and surface water impacts as possible. 2:1 roadway fill slope will be used in the wetland areas to minimize wetland impacts. Geotextile and Class II rip-rap was utilized
for bank stabilization to reduce stream bank erosion along the north and south bank of the channel underneath the bridge.
To avoid direct discharge of bridge storm water into the receiving water, deck drains are not required for the proposed bridge. Storm water impacts to the stream have been
minimized by utilizing grated inlets and pipes to collect bridge storm water and use rip rap outlet protection at 13+75 RT to dissipate energy to provide a diffuse flow (non-erosive
sheet flow) in a wooded area. This diffuse flow will run for a distance of 10'+/- in a special cut ditch before entering the buffer. At the same (SE) quadrant an existing roadside
ditch has outlet at 14+07 RT and will be turned out with a non-erosive outlet velocity. This diffuse flow runs for a distance of 40+/- before entering the stream. At the SW
quadrant there is an existing ditch that outlets at 13+99 LT with a non-erosive outlet velocity . The roadway is in fill section and runoff discharges as sheet flow off the pavement
through grassed shoulder and fill slope or wooded area to remove pollutants via infiltration and settling before entering the wetland or buffer on the west side of the road. In the
NW quadrant, there is an existing ditch that outlets at 15+13 LT with a non-erosive outlet velocity. This ditch will be retained and lined with toe protection along the fill slope. At
the NE quadrant an existing roadside ditch has outlet at 16+90 RT with a non-erosive outlet velocity. This diffuse flow runs for a distance of 20+/- before entering the wetland on
the northeast side of the bridge. This ditch will be retained. Due to the nature of low impact bridge replacement, the increases in stormwater discharges (post vs pre condition)
are insignificant and the existing ditches do not need to be modified. Therefore, additional stormwater measures are not required.
Waterbod Information
Surface Water Bod 1: Devils Cradle Creek aka Flatrock Creek er NCDEQ DWR NCDWR Stream Index No.: 28-78-1-12
NCDWR Surface Water Classification for Water Body Prima Classification: Class B
Supplemental Classification: NSW : +
Other Stream Classification: None
Impairments: None
A uatic T&E S ecies? No Comments:
NRTR Stream ID: Buffer Rules in Effect: Tar-Pamlico
Pro'ect Includes Brid e Spannin Water Bod ? Yes Deck Drains Dischar e Over Buffer? No Dissipator Pads Provided in Buffer? No
Deck Drains Dischar e Over Water Bod ? No (If yes, provide justification in the General Project Narrative) (If yes, describe in the General Project Narrative; if no, justify in the
(If yes, provide justification in the General Project Narrative) General Project Narrative)